46 research outputs found
Smooth transonic flows with nonzero vorticity to a quasi two dimensional steady Euler flow model
This paper concerns studies on smooth transonic flows with nonzero vorticity
in De Laval nozzles for a quasi two dimensional steady Euler flow model which
is a generalization of the classical quasi one dimensional model. First, the
existence and uniqueness of smooth transonic flows to the quasi one-dimensional
model, which start from a subsonic state at the entrance and accelerate to
reach a sonic state at the throat and then become supersonic are proved by a
reduction of degeneracy of the velocity near the sonic point and the implicit
function theorem. These flows can have positive or zero acceleration at their
sonic points and the degeneracy types near the sonic point are classified
precisely. We then establish the structural stability of the smooth one
dimensional transonic flow with positive acceleration at the sonic point for
the quasi two dimensional steady Euler flow model under small perturbations of
suitable boundary conditions, which yields the existence and uniqueness of a
class of smooth transonic flows with nonzero vorticity and positive
acceleration to the quasi two dimensional model. The positive acceleration of
the one dimensional transonic solutions plays an important role in searching
for an appropriate multiplier for the linearized second order mixed type
equations. A deformation-curl decomposition for the quasi two dimensional model
is utilized to deal with the transonic flows with nonzero vorticity.Comment: 54 page
3-D axisymmetric subsonic flows with nonzero swirl for the compressible Euler-Poisson system
We address the structural stability of 3-D axisymmetric subsonic flows with
nonzero swirl for the steady compressible Euler-Poisson system in a cylinder
supplemented with non small boundary data. A special Helmholtz decomposition of
the velocity field is introduced for 3-D axisymmetric flow with a nonzero
swirl(=angular momentum density) component.
With the newly introduced decomposition, a quasilinear elliptic system of
second order is derived from the elliptic modes in Euler-Poisson system for
subsonic flows. Due to the nonzero swirl, the main difficulties lie in the
solvability of a singular elliptic equation which concerns the angular
component of the vorticity in its cylindrical representation, and in analysis
of streamlines near the axis
Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1
Topics addressed include: wind tunnel and flight experiments; computational fluid dynamics (CFD) applications, industry overviews; and inviscid methods and grid generations
Aeronautical Engineering. A continuing bibliography with indexes, supplement 136, June 1981
This bibliography lists 424 reports, articles, and other documents introduced into the NASA scientific and technical information system in May 1981
Aeronautical engineering: A continuing bibliography with indexes (supplement 255)
This bibliography lists 529 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1990. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics